/*
 Copyright (c) 2024 HigginsSoft, Alexander Higgins - https://github.com/alexhiggins732/ 

 Copyright (c) 2018, Brock Allen & Dominick Baier. All rights reserved.

 Licensed under the Apache License, Version 2.0. See LICENSE in the project root for license information. 
 Source code and license this software can be found 

 The above copyright notice and this permission notice shall be included in all
 copies or substantial portions of the Software.
*/

namespace IdentityServer8.Extensions;

internal static class NameValueCollectionExtensions
{
    public static IDictionary<string, string[]> ToFullDictionary(this NameValueCollection source)
    {
        return source.AllKeys.ToDictionary(k => k, k => source.GetValues(k));
    }

    public static NameValueCollection FromFullDictionary(this IDictionary<string, string[]> source)
    {
        var nvc = new NameValueCollection();

        foreach ((string key, string[] strings) in source)
        {
            foreach (var value in strings)
            {
                nvc.Add(key, value);
            }
        }

        return nvc;
    }
    
    public static string ToQueryString(this NameValueCollection collection)
    {
        if (collection.Count == 0)
        {
            return String.Empty;
        }

        var builder = new StringBuilder(128);
        var first = true;
        foreach (string name in collection)
        {
            var values = collection.GetValues(name);
            if (values == null || values.Length == 0)
            {
                first = AppendNameValuePair(builder, first, true, name, String.Empty);
            }
            else
            {
                foreach (var value in values)
                {
                    first = AppendNameValuePair(builder, first, true, name, value);
                }
            }
        }

        return builder.ToString();
    }

    public static string ToFormPost(this NameValueCollection collection)
    {
        var builder = new StringBuilder(128);
        const string inputFieldFormat = "<input type='hidden' name='{0}' value='{1}' />\n";

        foreach (string name in collection)
        {
            var values = collection.GetValues(name);
            var value = values.First();
            value = HtmlEncoder.Default.Encode(value);
            builder.AppendFormat(inputFieldFormat, name, value);
        }

        return builder.ToString();
    }

    public static NameValueCollection ToNameValueCollection(this Dictionary<string, string> data)
    {
        var result = new NameValueCollection();

        if (data == null || data.Count == 0)
        {
            return result;
        }

        foreach (var name in data.Keys)
        {
            var value = data[name];
            if (value != null)
            {
                result.Add(name, value);
            }
        }

        return result;
    }

    public static Dictionary<string, string> ToDictionary(this NameValueCollection collection)
    {
        return collection.ToScrubbedDictionary();
    }

    public static Dictionary<string, string> ToScrubbedDictionary(this NameValueCollection collection, params string[] nameFilter)
    {
        var dict = new Dictionary<string, string>();

        if (collection == null || collection.Count == 0)
        {
            return dict;
        }

        foreach (string name in collection)
        {
            var value = collection.Get(name);
            if (value != null)
            {
                if (nameFilter.Contains(name, StringComparer.OrdinalIgnoreCase))
                {
                    value = "***REDACTED***";
                }
                dict.Add(name, value);
            }
        }

        return dict;
    }

    internal static string ConvertFormUrlEncodedSpacesToUrlEncodedSpaces(string str)
    {
        if ((str != null) && (str.IndexOf('+') >= 0))
        {
            str = str.Replace("+", "%20");
        }
        return str;
    }

    private static bool AppendNameValuePair(StringBuilder builder, bool first, bool urlEncode, string name, string value)
    {
        var effectiveName = name ?? String.Empty;
        var encodedName = urlEncode ? UrlEncoder.Default.Encode(effectiveName) : effectiveName;

        var effectiveValue = value ?? String.Empty;
        var encodedValue = urlEncode ? UrlEncoder.Default.Encode(effectiveValue) : effectiveValue;
        encodedValue = ConvertFormUrlEncodedSpacesToUrlEncodedSpaces(encodedValue);

        if (first)
        {
            first = false;
        }
        else
        {
            builder.Append("&");
        }

        builder.Append(encodedName);
        if (!String.IsNullOrEmpty(encodedValue))
        {
            builder.Append("=");
            builder.Append(encodedValue);
        }
        return first;
    }
}
